losing same channels all the time - DirecTV DVR

For losing same channels all the time, relating to DirecTV DVRs and receivers. Hi - I have a Hughes receiver that's about 6 years old and I'm trying to determine why I keep getting the the "searching for satellite signal" message for several channels. . it's always the same ones. I had the same problem last year, and a tech replaced the LNB, explaining that a bad connection was causing me to lose the signal when it got below a certain temperature outside. Now it seems to happen if it's the least bit cloudy outside... is this a dish or receiver problem? Or could the dish be slightly out of alignment?